Now that the WAAS minimums are going to be 200, same as
ILS, and the first WAAS approaches are going to be
overlaid over standard ILS approaches, the question
arises:

Which approach makes more sense to an ILS runway, use
of the ILS, or the WAAS?

Before you say "good ole ILS", consider: WAAS is going
to have many characteristics of an ideal precision system.
No false glideslopes, infinite range, no backcourse image,
etc.